Transcript for Sylvester Stallone on 'Rocky's Longevity, 'Bullet to the Head'

I'm here with sylvester stallone. You're listening to that theme music we all know and love so much. The superstar is back in action on the big screen, playing a hitman who joins forces with a cap, to avenge their partner's death. The movie is called "bullet to the head." We're happy to have sylvester stallone here to tell us about it. I was telling you off camera before you came out here, I was such a huge fan of "rocky." Now, my 6-year-old son plays clips of "rocky" nonstop on youtube. I don't know what to say? Is that a good thing? It's a great thing. You never get tired of watching the fight scene. I don't know what happened. I never intended it. It never ceases to amazes me, a young fella, approaching 100 years old, there's 6-year-olds still watching. It's amazing. Did you imagine -- no. My sons are in it. Every generation of boys loves it. It's a freak of nature. I don't blame authorship to it. You have a new movie out. It's based on a book called "bullet." Why did you pick this one? I wanted to do a graphic novel. I wanted to do something beyond the realm of realism. But still in my wheelhouse. I wanted to do a buddy film. But it's really not a buddy film. I hate this guy. He hates me. Therefore, an anti-buddy film. And walter hill, a great He was a key I wanted to work with, these people while they're still in their creative state. You had said you wanted to work with walter hill in the movie "48 hours" but you passed on that role. I was dumb. I passed on a lot of things. Which do you wish, looking back, you had taken that you passed on? "Coming home." Let me see. I did "rhinestone." And there was chasing some stone. With michael douglas. "Romancing the stone"? I took the wrong stone. There's a lot of things. "Witness." "Witness"? You were offered a role in "witness"? Things like that. Wow. You make these mistakes and you move on. You do what you do well and give people what they want. You mentioned "rhinestone." You were saying a moment ago, with the great andrea bocelli, if he needs any singing help. He does need some pointers. Andrea, open. Breathe. You heard me in "rhinestone." &#9834; Last night I went hononk &#9834; is heoming over? Is he going to punch me? I think my 6-year-old is really going to wish he is here. He's my man. He's great. We have a quick clip of this movie, where you're talking with the partner you can't stand, about how he's going to tell you how a cell phone can be used as a murder weapon. And you give him a little lesson. Let's take a look. I can break this glass and use it as a cutting edge. Never see me coming. I could use a lithium battery to poison your drink and in your coffee. Wouldn't even taste it. And I could kill you with this piece of apple. Yeah, right. How would you do that? Distraction. You mentioned in this movie, you used your voice in a way you never have before. You call it full voice. Tell us about that. Well, usually, rambo, he's kind of reserved. He doesn't open up. Rocky, it's more nasal. Why don't I just pretend, for once, that I am actually a hitman. You don't try to do any character work. You just go out there and say, okay. Let me see. I'm a father of three. But today, I'm a hitman. But I have the same personality. See what I mean? It's kind of interesting. A lot of times it's more interesting to try to be someone else. Well, it's not me. It's someone else. I'm a good guy. It was a bad character. I said, let me try to be me. And you're going to go in the boxing ring one more time with robert de niro. Oh, my god. You described it -- it's for warner brothers. It's called "grudge match." It's amazing. I've never had so much fun. We get in the ring and get it on. Aren't they approaching the century mark yet? Yes, we are. We're a little younger than the constitution. But, you know, most guys combined average age, 41. We're like 135. But we're just kids with arthritis. We really are. We're ready to go for it. Trust me, my sons would love to be extras on that set. Yeah. Thank you. It's great to have you here this morning. "Bullet to the head" opens nationwide on friday. A love story. A love story. I love you, my bullet.

This transcript has been automatically generated and may not be 100% accurate.

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